This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. hbAP-CN is a halothane binding amphiphilic peptide which forms a 4-helix bundle in aqueous detergent buffer solution. Halothane, an inhalational general anesthetic, binds to the cavity in the hydrophobic core of the bundle. A fluorophore incorporated into each peptide helical strand, cyano-phenylalanine (Phe-CN) is located right next to the halothane binding site. Halothane is known to quench fluorescence when it binds to hbAP-CN. The goal of doing a fluorescence study including the measurement of fluorescent spetra and lifetimes as a function of halothane concentration is to better understand the binding site and quenching mechanism (static or dynamic). It it planned to measure fluorescence lifetimes at the Resource using 270nm excitation (tripled Ti:sapphire laser) of hbAP-CN and Phe-CN itself.